With the trend for smaller hand held devices, such as cell phones, and the need to continue to generally reserve surface space for the positioning of interactive elements for purposes of enabling the user to interact with the device, the use of touch sensitive displays, which enable a device to visually convey information to a user, as well as enable a user to interact contextually with displayed object and otherwise provide user input to the device is increasingly being used. Touch sensitive displays merge input and output functions for some portable electronic devices, which in absence of the use of a similar and/or alternative form of input/output merging capability might otherwise require their own dedicated portions of the device surface. For example, many devices have historically incorporated a separate display and keypad on distinct portions of the external surface of the device.
However, some device designs have been able to extend the size of the display by extending it to include the surface space of the device that might otherwise have been separately dedicated to the location of a keypad. In some such instances, keypad-like input capabilities have been provided and/or maintained through the use of touch sensitive capabilities built into the extended display. One of the benefits of such a merger is the ability to dynamically change the size, shape and arrangement of keys, where each key can correspond to a subset of the surface space of the touch sensitive display associated therewith. Furthermore, each key can be accompanied by a visual indication, generally, through the integrated display, and more specifically the portions of the display that are currently active for providing each currently permissible form of user key selection and/or the immediately adjacent portions.
However one of the difficulties associated with touch screen displays includes the possibility that portions of the display become obstructed by one's fingers or hands in circumstances during which the user is simultaneously attempting to provide user input through the touch sensitive display interface, while one is attempting to view the information being presented via the display. Furthermore, interaction with the display with one's fingers can often leave smudges, which while they do not generally affect the operation of the device, can sometimes affect the appearance of the device, and may also impact the perceived image quality.
Consequently, some devices have incorporated touch sensitive surfaces that are located on the back side of the device, which are intended for use by the user to interact with and/or select items, which are being displayed on the front side of the device. However sometimes it can be less than clear which location on the front facing display corresponds to particular position being currently touched on the back of the device.
The use of a touch sensitive surface not only allows for the location of an interacting object, such as a pointer, to be identified by the device, but the movement of the interacting object can be similarly tracked as a function of time as the interacting object moves across the touch surface, in many instances. In this way, it may be possible to detect gestures, which can be mapped to and used to distinguish a particular type of function that may be desired to be implemented relative to the device and/or one or more selected objects. In some instances, multiple pointer gestures have been used to more intuitively identify some desired functions, such as the two finger pinching or spreading motion, which has sometimes been used to zoom in and zoom out.
However, multi-pointer gestures have generally been defined relative to a single touch sensitive input surface. Further, when one holds a device it is common for one's hand to wrap around the side of the device from the back of the device to the front of the device. Correspondingly, the present inventors have recognized that it would be beneficial to enable interactions with multiple sides of the device to be tracked for purposes of defining interactive gestures including interactive gestures involving multiple pointers, and for purposes of detecting the same. In this way some gestures can be integrated and or made more compatible with an action which is similarly intended to grip or hold an object. Still further, the present inventors have recognized that it would be beneficial if the user could more readily correlate a particular point associated with the back of the device, with which the user is currently interacting, and the corresponding point or object being displayed on the screen, which is visible via the front of the device.